Information received during an FAA investigation into suspected unapproved parts indicates that Temperform USA, formerly of Mirada, Calif., had improperly heat-treated numerous aluminum parts that have aviation applications. Temperform was approved to perform heat-treating for many production approval holders.
The investigation disclosed that from May 1998 to September 2001, Temperform improperly heat-treated and falsified quality testing on parts that are used in various type-certified aircraft. Regulations require that type-certified products conform to their type design.
Aircraft owners and operators, manufacturers, maintenance organizations and parts suppliers and distributors should inspect their aircraft, aircraft records and/or parts inventories for the referenced part numbers. If any are found in existing stock, the FAA recommends that the parts be quarantined to prevent installation until a determination can be made regarding their eligibility for installation.
The parts in question do not display any readily identifiable external features
or markings to distinguish them from properly heat-treated parts; therefore, documentation associated with the parts should be reviewed to determine the source of heat-treating. Parts heat-treated by Temperform may require hardness and/or conductivity testing.

The FAA has a list containing 4,148 distinct parts that affect a wide range of transport-category, business and general aviation aircraft, including the Boeing 707, 717, 727, 737, 747, 757, 767, 777, DC-8, DC-9, DC-10, MD-11, MD-80 and MD-90; MD Helicopters 369D; Bell/Agusta AB139; Airbus A320/321 and A340; Beech 400; Bell 212, 206, 430; Bombardier Global Express, Challenger 600, Challenger 601, Learjet 45; BAE 146; Saab 340; de Havilland Dash 8; Cessna Citation, Citation 650, Citation 750, Cessna Ultra Encore 560; Dornier 328; Galaxy, G200, Gulfstream GV; and parts for Rolls-Royce, Pratt & Whitney and GE aero engines. The full listing is available at www.faa.gov/avr/sups/upn/temperform.xls.